The invention relates to a packaging structure for a ring-shaped product or disk-shaped product (such as a roll of magnetic tape called "pancake").
A magnetic tape intended to be loaded in a tape cassette or the like is, in the manufacturing process, wound around a hub with a specific tension, and is formed into a pancake of a specific diameter for storage or transportation.
FIGS. 46 and 47 respectively illustrate a conventional transportation tray 128 for a pancake.
The tray 128 has a substantially octagonal-shaped tray proper 122 made of foamed polystyrene; a pancake housing area 123 formed on the tray proper 122; and ring shaped cushions 125 and 126 made of foamed polyethylene and are disposed (with adhesive) on both upper and lower faces of the tray. The tray 122 has in its center a disc shaped projection 127, thereby as shown in FIG. 47, centering around the projection 127 and on the cushion 125 is loaded a pancake 2 (a magnetic tape 3 wound around a hub 4).
To facilitate transportation or storage, a plurality of trays 128 are vertically stacked as shown in FIG. 47 (for clarity, this figure illustrates only two stages of trays), wherein a pancake 2 is held sandwiched between the cushions 126 and 125 of the upper and lower trays. Once satisfactorily stacked, whole the stacked trays are bound together with a binding band 129, and are wrapped with a heat shrinkable film 130 by heat shrinking process, thus package is complete.
Since such a pancake packaging structure requires each pancake to be packed in each transportation tray, thus necessitating a multiplicity of trays, incurring a higher cost for transportation and the like, and, manufacturing and maintenance costs for the trays are higher; procedures for loading and unloading pancakes for transportation and storage are cumbersome and time-consuming.